1. Field of the Invention
This invention relates to a rotor for a magneto generator, and specifically to a rotor that revolves synchronously with an engine, and has a magnet, the flux of which interlinks with a stator coil for generating electric power.
2. Description of Prior Art
In a small internal combustion engine, a magneto generator is used to create electric power for providing ignition to the engine. The generator has a rotor with a magnet, and a stator coil stationarily situated on the outside of the magnet. When the rotor revolves, the flux of the magnet interlinks with the stator coil to generate electric power which ignites the engine.
When an engine with this kind of magneto generator is used on a machine that is hand held, for example a chainsaw, or manually manipulated, for example a lawn mower, the engine should be light, otherwise the operator of the machine will immediately become tired. Also the efficiency of the work performed by the engine is lowered when the engine is heavy. For these reasons, the rotor of the magneto generator of the engine should be light.
Generally, one skilled in the art would directly consider forming the rotor using molded resin to lighten the rotor. But it is impossible for such a molded rotor to bear the centrifugal force of the number of revolutions of the rotor, which is more than 15000 rpm, causing the rotor will be broken by the high-speed revolution. Therefore the conventional rotor of the magneto generator is made through a die casting method by aluminum alloy. The aluminum rotor is heavy relative to a resin rotor, and includes many parts which make assembly troublesome, thus raising the cost of the rotor.